perfect murder

MODS IS THIS ALLOWED? If so...
i am writing a paper for school(forensic science class) and i need to make the perfect murder... i have quite a few ideas but i just wanted to see how twisted you myloters were
WARNING!!!!!!!!!!! this topic is already on the edge so be careful with what you put make sure it is kept professional if you know what i mean. don't go into gory details or perverted things AND no kids, animals, or rape. those are immediate discussion closers

Stab someone with a dagger made of ice. It will melt so there's no physical evidence to it. Wash you hands right away but i prefer you use surgical gloves just to be sure you won't leave your dna. Burn your clothes most especially your shoes. They might leave tracks. For the difficult part, try to text (..or make a call) someone while you're a few minutes after the murder, preferably a question so there's no suspicion that you're doing the killing because you're busy with another friend on the other side of the phone. This is impromptu but i can do better if i need a few more minutes to think hehe..

ahh but the problem is that they can see were the call was made from. so youd have to set it up so you would call someone and have a voice rec. so that it sounds like you from your house while you are doing the deed